Method for purifying and improving the surface quality of an ingot



Uniteustates Patent- [72] Inventors Roy E. Ferree; V

Edward P. Vincent, Valencia, Pennsylvania [21] AppLNo. 719,218

[54] METHOD FOR PURIFYING AND IMPROVING THE SURFACE QUALITY OF AN INGOT 1 Claim, No Drawings [52] U.S.Cl 164/74, 106/38.25, 106/38.8, 117/51 [51] Int. Cl B224: 3/00, n 822d 27/00 -[$0] Fleldotseerch ,.'164/74,72, 73,67, 42US, 121; 106/38.25, 38.8; 117/51.-

[56] References Cited UNITED STATES PATENTS 1,751,038 3/1930 Hoy 164/67 1,849,767 3/1932 Michel 164/42 1,868,453 7/1932 Wood... 164/42 1,868,454 7/1932 Wood... 164/42 1,868,455 7/1932. Wood... 164/42 1,868,456 7/1932 \Vood.... 164/42 1,868,457 7/1932 Wood 164/42 2,236,119 3/1941 Craigetal. 164/72X 2,245,651 6/1941. Craig etal. l64/72X 2,430,655 11/1947 Wallace 164/74 OTHER REFERENCES Processing Molding Sand By Harry W. Dietent, Transactions of The American Foundrymen s' Society Vol. 62, (1954), p. 8 relied on.

Primary Examiner-J. Spencer Overholser Assistant Examiner-V. Rising Altomey- William J. Ruano ABSTRACT: This invention relates to a method of purifying, reducing surface imperfections and of lubricating the outer surface of an ingot to facilitate removal from the mold, comprising reacting napthalene in powder or liquid form by pouring molten metal thereon in an ingot mold or pouring the napthalene during teeming thereby creating an inert and dense cloud of carbonaceous smoke that will rise in the mold and prevent oxidation and that will coat the inner surface of the mold and outer surface the ingot. Various organic and inorganic compounds are mixed in specified proportions with the naphthalene.

SURFACE QUALITY or'xn moor This invention relates to a novel method of purifying, reducing surface imperfections and lubricating an ingot as molten metal is'poured into the mold. This inventionis'a continuation-in-part of my US. Pat. application Ser. No. 627,283, filed March 31, 1967, now abandoned. v

An'outstanding disadvantage of presently used methods of casting ingots'is thatimperfections'areformed on the outer surface thereof, many .of which are caused by abrasion or friction resulting from'removal of the ingot from the mold and from scabs and splashes reduced or eliminated by this invention.

Another disadvantage is that oxidation of molten steel takes I place during the teeming of this metal since the surrounding atmosphere contains oxygen.

An object of the present invention is'to overcome the above-nameddisadvantages of present methods and to pro-- vide a novel'method for greatly reducing surface imperfections of the ingot and atthe-same time facilitating removal of the ingot' by lubricating" the inner'surface of the mold and outer surface of the ingot as the result-of the teeming process.

A more specific object of the invention is to pour molten metal, such as molten steel, into an ingot mold which'contains napthalene mixed with organic or inorganic compounds on the bottom, or on its inner surfaces, or to pour the napthalene mixture during teeming so as to facilitate removal and greatly enhance the quality of the outer surface of the ingot by creat ing an inert atmosphere that eliminates oxidation of the molten steel. i l

The term napthalene as used in my disclosure is the material fhaphthalene" described at page445of the 4th Ed. of HACKl-ls CHEMICAL DlCTlONARY, copyright 1969 by McGraw-Hill, lnc.,.

' Other objects and advantages of the invention will become more apparent from a study of. the following description.

A mold coating, embodying the present invention, may be manufactured by empioyingat least 70 percent napthalene and the remainder of other organic or inorganic materials which serve as binders, as stabilizers, as coloring agents, or as release agents, partingmedia and deoxidizers. A suitable range of napthalene per ingot ton of the ingot cast isfrom about 1/16 pound to about 5 pounds. This napthalene could be used either as a dry powder 'or as a liquid which is then allowed to solidify into a solid mass:

We have conducted successful tests involving the addition, in amounts of l to 30 percent by weight to' the napthalene of each of the following organic compounds: graphite; Gilsonite; petroleum coke; powdered coke; coke breeze; coal; pitch (in many forms); tar (in critical. We have also conductedother successful tests in which the following inorganiecompounds were added to napthalene:

' limel to percent; silicia-l to 7% percent; clay- I to l0 percent; iron oxide- 1 to '15 percent and a binder, namely, sodium silicate A to 4% percent.

Tests indicate inorganic additions must be in a finely divided form,such assilica flower, 200 mesh by down. The lar gest particle size experimented with so far has been 100 mesh and down. it appears that coarser-sizes will give less satisfacto' ry results.

The napthalene powder or liquid mixture so formulated is introduced into the ingot mold just prior to pouring. it may be deposited on the bottom inflow of the mold or on the entire inner surface. When this material is contacted by the molten steel it begins to generate and pour forth a dense cloud of carbonaceous smoke that rises in the mold on top of the molten steel. This reactionimparts, simultaneously, a coating on the outer surface of the ingot and on the inner surface of the ingot mold, at the same time, provides an inert atmosphere that prevents oxidation of the molten steel during the teeming process, thereforegreatly enhances the purity or quality of the inished steel ingot. The net result is also a substantial reductron in surface imperfections of the ingot due to the inability of the splash or scab to cling to the mold wall, as well as lubrication of the outer surface of the ingot and inner surface of the mold which will facilitate removal of the solidify ingot from the mold and further reduce imperfections otherwise formed on the surface of the ingot as a consequence of abrasion or friction. Thus the surface 'quality and the quality of the interior of the ingot are greatlyen'hanced and, as a consequence, all

losses-in the further processing or finishing of the steel are reduced.

Although napthalene has been given as an exampleof a material that will generatea carbonaceous cloud of smoke as the result of the teeming process when used alone or mixed withorganic orinorganic materials, other derivatives of may forms); and sizing of particles is not napthalene or other equivalent materials will be readily suggested. to those skilled in the art as the result of the present description, but which materials are considered within the spirit and scope of the present invention.

While I have described several embodiments of my invention, it will be understood that these are by way of illustration only, and that various changes andmodificati'ons may be made within the contemplation of my invention and within the scope of the following claims.

We claim:

1. The method of purifying, reducing surface imperfections and lubricating an ingot'comprising:

introducing into an ingot mold just prior to pouring a composition consisting essentially of at least percent naphthalene mixed with l to 30 percent, by weight, of Gilsonite and teeming molten. metal into said mold and into contact with said composition and thereby causing said composition to react so as to form a dense, continuous, carbonaceous cloud which coats the outer surface of the ingot and inner surface of the mold. 

